Abstract: This paper presents an approach on the advantages of using adequate coverage in the zenithal lighting typology in various areas of architectural production, while at the same time to encourage to the design concerns inherent in this choice of roofing in Brazil. Understanding that sustainability needs to cover several aspects, a roofing system such as zenithal lighting system can contribute to the provision of better quality natural light for the interior of the building, which is related to the good health and welfare; it will also be able to contribute for the sustainable aspects and environmental needs, when it allows the generation of energy in semitransparent or opacity photovoltaic solutions and economize the artificial lightning. When the energy balance in the building is positive, that is, when the building generates more energy than it consumes, it may fit into the Net Zero Energy Building concept. The zenithal lighting systems could be an important ally in Brazil, when solved the burden of heat gains, participate in the set of pro-efficiency actions in search of "zero energy buildings". The paper presents comparative three cases of buildings that have used this feature in search of better environmental performance, both in light comfort and sustainability as a whole. Two of these buildings are examples in Europe: the Notley Green School in the UK and the Isofóton factory in Spain. The third building with these principles of shed´s roof is located in Brazil: the Ipel´s factory in São Paulo.
Abstract: In most existing buildings in hot climate, cooling
loads lead to high primary energy consumption and consequently
high CO2 emissions. These can be substantially decreased with
integrated renewable energy systems. Kuwait is characterized by its
dry hot long summer and short warm winter. Kuwait receives annual
total radiation more than 5280 MJ/m2 with approximately 3347 h of
sunshine. Solar energy systems consist of PV modules and parabolic
trough collectors are considered to satisfy electricity consumption,
domestic water heating, and cooling loads of an existing building.
This paper presents the results of an extensive program of energy
conservation and energy generation using integrated photovoltaic
(PV) modules and Parabolic Trough Collectors (PTC). The program
conducted on an existing institutional building intending to convert it
into a Net-Zero Energy Building (NZEB) or near net Zero Energy
Building (nNZEB). The program consists of two phases; the first
phase is concerned with energy auditing and energy conservation
measures at minimum cost and the second phase considers the
installation of photovoltaic modules and parabolic trough collectors.
The 2-storey building under consideration is the Applied Sciences
Department at the College of Technological Studies, Kuwait. Single
effect lithium bromide water absorption chillers are implemented to
provide air conditioning load to the building. A numerical model is
developed to evaluate the performance of parabolic trough collectors
in Kuwait climate. Transient simulation program (TRNSYS) is
adapted to simulate the performance of different solar system
components. In addition, a numerical model is developed to assess
the environmental impacts of building integrated renewable energy
systems. Results indicate that efficient energy conservation can play
an important role in converting the existing buildings into NZEBs as
it saves a significant portion of annual energy consumption of the
building. The first phase results in an energy conservation of about
28% of the building consumption. In the second phase, the integrated
PV completely covers the lighting and equipment loads of the
building. On the other hand, parabolic trough collectors of optimum
area of 765 m2 can satisfy a significant portion of the cooling load,
i.e about73% of the total building cooling load. The annual avoided
CO2 emission is evaluated at the optimum conditions to assess the
environmental impacts of renewable energy systems. The total annual
avoided CO2 emission is about 680 metric ton/year which confirms
the environmental impacts of these systems in Kuwait.